Zwitterionic Gel Coating Endows Gold Nanoparticles with Ultrastability

Abstract

Colloidal stability of gold nanoparticles (GNPs) is of great importance for their applications. Although a number of ligands have been developed to protect GNPs, irreversible aggregation still happens under some particular conditions. Herein, we report a zwitterionic encapsulation strategy to endow GNPs with ultrastability. Each single GNP is coated with a cross-linked zwitterionic poly(ornithine methacrylamide) hydrogel thin-layer, which prevents particle aggregation under extremely harsh conditions, including lyophilization, strong acid solution, saturated salt solution, and concentrated alkali solution. In addition, the zwitterionic gel layer resists protein adsorption in the biological milieu, keeping the nanoparticles stable in full human blood serum. Furthermore, the amino-acid-derived polymer gel provides numerous conjugation sites for on-demand biomolecular functionalization. With all these merits, the zwitterionic gel coated GNPs hold great potential in many applications such as sensing and theragnostics.

Mucopenetrating Zwitterionic Micelles

“…The number of used monomers to synthesis polyzwitterions is rather limited focusing on phosphobetaine, carboxybetaines, 2‐methacryloyloxyethyl phosphorylcholine, and sulfobetaines. However, alternative monomers such as serine methacrylate and ornithine methacrylamide to obtain amino‐acid‐based zwitterionic polymers, or a zwitterionic dopamine derivative started to emerge. Zwitterionic materials are essential for life illustrated by specific phospholipids or osmolytes, inspiring scientists in material design.…”

“…Zwitterionic homo‐ and copolymeric hydrogels are explored towards their tailorable swelling and absorption behavior, their antimicrobial protein‐resistant and cytophobic properties, as self‐healing material, or to control the differentiation of mesenchymal stem cells among others. Further, integrating zwitterionic polymers into colloidal assemblies was explored including their use as surface coating of solid nanoparticles, as emulsified (cargo‐loaded) nanoparticles, or as building blocks in polymer micelles and vesicles . In the context of mucopenetration, polyzwitterions remain largely unexplored.…”

Recent Progress of Carbon Dot Precursors and Photocatalysis Applications

“…Aggregation of nanoparicles is a serious problem, which hinders their applications in drug delivery, imaging, and other fields [68,69]. To address the problem, a unique group of synthetic polymers, named “zwitterionic polymers” which contain equimolar anionic and cationic groups in their structures, were recently explored to derive ultra-stable and fluorescent CDs through a simple one-step microwave heating method (1000 W, 5 min) [70].…”

“…To address the problem, a unique group of synthetic polymers, named “zwitterionic polymers” which contain equimolar anionic and cationic groups in their structures, were recently explored to derive ultra-stable and fluorescent CDs through a simple one-step microwave heating method (1000 W, 5 min) [70]. The zwitterionic polymers are well known for their superhydrophilic and antifouling properties in resisting nonspecific binding from proteins, cells and microorganisms and have been widely used to protect nanoparticles from aggregation [68,69,71,72,73,74,75,76]. In Wang’s work [70], four zwitterionic linear polymers (Mw = 8–10 k) were explored, including poly(sulfobetaine), poly(carboxybetaine)-2, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and poly(carboxybetaine)-1 (PCB-1).…”

Facile Synthesis of Peptide-Conjugated Gold Nanoclusters with Different Lengths

“…Gold nanoparticles, particularly gold nanospheres [1][2][3][4][5][6][7][8] (Au NSs, size < 200 nm) and gold nanoclusters [9][10][11][12][13][14][15][16][17] (Au NCs, size < 2 nm), have received growing attention in recent years because of their excellent optical and electronic properties [18][19][20]. Many biomoleculeconjugated Au NSs have been prepared, such as peptide, protein, and DNA, which have a potential use in many biomedical and biosensing applications [21][22][23][24][25][26][27][28][29]. Typically, the peptides are conjugated to the surface of gold nanoparticles through the Au-S bond which was formed between the cysteine and gold [30][31][32][33].…”